scholarly journals A new method of filtering T waves to detect hidden P waves in electrocardiogram signals

EP Europace ◽  
2011 ◽  
Vol 13 (7) ◽  
pp. 1028-1033 ◽  
Author(s):  
D. Goldwasser ◽  
A. Bayes de Luna ◽  
G. Serra ◽  
R. Elosua ◽  
E. Rodriguez ◽  
...  
Keyword(s):  
New Method ◽  
P Waves ◽  
Electrocardiogram Signals ◽  
T Waves

scholarly journals Physiological ECG Value for Polish Half-Bred Anglo-Arab Horses

2012 ◽  
Vol 56 (4) ◽  
pp. 631-635 ◽  
Keyword(s):  
Heart Rate ◽  
P Wave ◽  
P Waves ◽  
T Wave ◽  
Duration Time ◽  
Qt Intervals ◽  
Electrocardiographic Examination ◽  
Electrocardiographic Findings ◽  
Almost All ◽  
T Waves

Abstract The electrocardiographic examination was performed in 33 training horses (2-16 years of age, 11 males and 22 females). Einthoven and precordial leads (I, II, III, aVR, aVL, aVF, CV1, CV2, CV4) were used. The ECG was performed in resting horses and immediately after exercise (10 min walk, 15 min trot, 10 min canter) using a portable Schiller AT-1 3-channel electrocardiograph, with a paper speed of 25 mm sec-1 and a sensitivity of 10 mm.mV-1. The heart rate, wave amplitudes, and duration time were estimated manually. All horses presented a significant increase in heart rate after exercise (rest 43.83 ±10.33 vs. exercise 73.2 ±14.8). QT intervals were significantly shortened in most of the leads. In resting horses, all P waves in the lead I were positive and almost all II, III and CV4 leads were positive. Simple negative P wave dominated in aVR and only simple negative T wave was found in the leads I. The biphasic shape was observed. After exercise, the amplitude of P and T waves rose, however, clear changes were not observed in wave polarisation and form. In the absence of specific racial characteristics of the electrocardiogram in the Polish Anglo- Arabians, electrocardiographic findings can be interpreted according to ECG standards adopted for horses.

Electrocardiography

2020 ◽  
pp. 3294-3314
Author(s):  
Andrew R. Houghton ◽  
David Gray
Keyword(s):  
Myocardial Infarction ◽  
Electrical Activity ◽  
19Th Century ◽  
Diagnostic Tool ◽  
Posterior Aspect ◽  
P Waves ◽  
Right Ventricular Myocardial Infarction ◽  
The 19Th Century ◽  
Ventricular Depolarization ◽  
T Waves

The electrocardiograph (ECG) has been recognized as a valuable diagnostic tool since the end of the 19th century. The normal ECG waveform consists of P, QRS, and T waves (and sometimes U waves)—P waves result from atrial depolarization, QRS complexes from ventricular depolarization, and T waves from ventricular repolarization. The standard 12-lead ECG utilizes four limb electrodes and six precordial electrodes to generate 12 leads or ‘views’ of the heart’s electrical activity. There are six limb leads (termed I, II, III, aVR, aVL, and aVF) and six precordial leads (termed V1, V2, V3, V4, V5, and V6). Supplementary ‘views’ can be obtained by using additional leads, such as V7, V8, and V9 to assess the posterior aspect of the heart and right-sided chest leads to look for a right ventricular myocardial infarction.

P5016Usefulness of different electrocardiographic patterns as predictors of in-hospital mortality in acute pulmonary embolism

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
P Alarcon ◽  
J A Bilbao ◽  
R Melchiori ◽  
I M Cigalini ◽  
C E Scatularo ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Hospital Mortality ◽  
Acute Pulmonary Embolism ◽  
Sinus Tachycardia ◽  
P Value ◽  
P Waves ◽  
St Segment Elevation ◽  
St Segment ◽  
Acute Pe ◽  
T Waves

Abstract Background Many electrocardiographic (ECG) patterns may be present in acute pulmonary embolism (PE), but their prevalence and association with in hospital mortality (IHM) are less well established. Objective Assess the correlation between different ECG patterns and IHM in patients (Pts) with PE using a whole country dataset. Methods Prospective multicenter registry which included Pts with acute PE hospitalized in 75 academic centers from October 2016 to November 2017. We considered the following ECG patterns: sinus tachycardia, pulmonary P waves, Q waves in DII-aVF leads, negative T waves in V1-V4, ST segment elevation in aVR and V1, atrial fibrillation or atrial flutter (AF/AF), right bundle branch block (RBBB), ST segment depression, S1Q3T3 pattern or Qr in V1. Statistical analysis was carried out using de STATA version 13.1. A value of p<0.0.5 was considered statistically significant. Results We included 684 Pts; mean age 63.8±16.7 years (43% male). Global IHM was 12%. The most prevalent ECG patterns were sinus tachycardia (51.7%), S1Q3T3 (24.5%), negative T waves in V1- V4 (16%), RBBB (9.9%), AF/AF (8.6%). Four ECG patterns remained statistically significant predictors of IHM on multivariate analysis: AF/AF (OR: 3.81; CI 95% 1.82–7.95, p<0.01), pulmonary P waves (OR: 3.81; CI 95% 1.2–12, p<0.04), RBBB (OR: 2.71; CI 95% 1.39–5.30, p<0.01) and sinus tachycardia (OR: 2.05; CI 95% 1.18–3.54, p<0.04). ECG pattern and in-hospital mortality.Multivariate analysis Electrocardiographic pattern OR CI 95% p value AF/AF 3.81 1.82–7.95 <0.01 Pulmonary P waves 3.81 1.20–12.00 <0.04 RBBB 2.71 1.39–5.30 <0.01 Sinus tachycardia 2.05 1.18–3.54 <0.04 Q waves in DII-aVF 0.93 0.32–2.64 0.89 ST segment depression 1.07 0.39–2.96 0.80 Negative T waves in V1-V4 0.93 0.47–1.81 0.83 S1Q3T3 pattern 0.75 0.39–1.41 0.37 Qr in V1 2.07 0.63–6.73 0.22 ST segment elevation in aVR 2.38 0.79–7.15 0.12 Conclusions We corroborate the usefulness of the ECG as a prognostic tool in acute PE. Four simple ECG patterns (AF/AF, Pulmonary P waves, RBBB and sinus tachycardia) were associated with a higher IHM and therefore should be considered for PE risk stratification.

Seismic T-Wave Observations at Dense Seismic Networks

2020 ◽  
Vol 91 (6) ◽  
pp. 3444-3453
Author(s):  
Catherine D. de Groot-Hedlin
Keyword(s):  
Wave Propagation ◽  
West Coast ◽  
East Coast ◽  
Seismic Energy ◽  
Polarization Analysis ◽  
The West ◽  
P Waves ◽  
Transverse Waves ◽  
T Wave ◽  
T Waves

Abstract Seismic T waves, which result from transformation of hydroacoustic to seismic energy at coastlines, were investigated for two strong earthquakes. A 2014 Caribbean event generated seismic T waves that were detected at over 250 seismometers along the east coast of the U.S., primarily at seismic stations operated by the USArray Transportable Array. A 2006 Hawaiian event generated seismic T waves observed at over 100 seismometers along the west coast. Seismic T-wave propagation was treated as locally 2D where the incoming hydroacoustic wavefronts were nearly parallel to the coastlines. Along the east coast, seismic T-wave propagation velocities were consistent with surface waves and a polarization analysis indicated that they were transverse waves, supporting their interpretation as Love waves. They were observed at inland distances up to 1134 km from the east coast. Along the west coast, the propagation velocity was over 5  km/s and a polarization analysis confirmed that the seismic T waves propagated as seismic P waves. Differences between the modes of propagation along the east and west coasts are attributed to differences in the slope and thickness of the sediment coverage at the continental slopes where hydroacoustic to seismic conversion takes place.

Abstract 13730: Electrical Axes of P and T but Not QRS Waves on ECG Are New Indicators of Successfulness of the Nuss Operation for Pectus Excavatum Considering Anatomical Severity as Indicated by the Haller Index Acquired by CT

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Nobusada FUNABASHI ◽  
Yoshio Kobayashi
Keyword(s):  
Pectus Excavatum ◽  
Correlation Coefficients ◽  
P Wave ◽  
Invasive Technique ◽  
P Waves ◽  
Haller Index ◽  
Before And After ◽  
Group 2 ◽  
Group 1 ◽  
T Waves

Introduction: Pectus excavatum (PEX) is a depression of the sternum which can physically constrict the heart and cause abnormal ECGs. The Nuss operation is a minimally invasive technique for PEX repair. Hypothesis: As right (RA) and left atria (LA) are compressed in PEX, axes of P, QRS, and T waves are abnormal and the Nuss operation normalizes them. We also took the Haller index (HI) into to account. Methods: 17 PEX patients (14 male, 12±6 years) underwent CT and ECG before and after the Nuss operation. Results: All Nuss operations were successful, and HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). There were no significant differences before and after surgery for electrical axes of P waves (46±20 vs 65±55, P=0.20), and QRS waves (75±33 vs 76±23, P=0.72), but T waves were greater thereafter (22±27 vs 40±19, P=0.001). Correlation coefficients (CC) between the degree of axes of P, QRS and T waves, and HI before operation were -0.23, -0.06, and 0.11, respectively. These values after operation were -0.25, -0.06, and 0.19, respectively. As HI is an indirect indicator of heart compression, we evaluated the degree of RA and LA compression qualitatively as none, mild, and moderate/more. Of 17 patients, 5 had moderate/more compression of RA and/or LA by PEX (group 1); the remaining 12 did not show compression (group 2). Only P wave values were significantly smaller in group 1 than 2 before surgery, but these differences disappeared after surgery. In both groups, degree of axes of T waves was significantly greater after the operation. Conclusion: In patients with PEX, axes of T waves after the Nuss operation became significant greater than before the operation in patients with moderate or more compression of RA and/or LA by PEX. For P waves, this was smaller before the operation in those with compression but this was improved by the Nuss operation. P and T wave axes but not QRS could be therefore non-invasive indicators of Nuss operation success in addition to gross PEX appearance.

scholarly journals Variability Inter-observer between Three Methods of Electrocardiographic (Conventional, Computerized and Computerized Printed) on Healthy Cats

2020 ◽  
Vol 48 ◽  
Author(s):  
Mariana Yukari Hayasaki Porsani ◽  
Luiz Eduardo Duarte de Oliveira ◽  
Ruthnea Aparecida Lázaro Muzzi ◽  
Claudine Botelho De Abreu ◽  
Camila Santos Pereira ◽  
...  
Keyword(s):  
Heart Rate ◽  
Conventional Method ◽  
Single Channel ◽  
P Wave ◽  
Similar Degree ◽  
P Waves ◽  
Computerized Method ◽  
St Segment ◽  
St Segments ◽  
T Waves

Background: Electrocardiography is an exam widely used in feline medicine. It consists of recording the electrical activity of the heart in waves representing myocardial depolarization and repolarization. Two electrocardiographic evaluation methods are employed in dogs and cats: computerized and conventional. However, possible differences in ECG results performed by the different methods have been reported. This paper aims to evaluate the observer's interference in the interpretation of the electrocardiographic exams and possible differences between the methods: conventional single channel, computerized screen and computerized printed of healthy cats.Materials, Methods & Results: Electrocardiographic tracings were obtained from 58 healthy cats, aged between 1 and 10 years-old, of both sexes, of the Persian and mixed breed and therefore interpreted by four observers with similar degree of experience. The examinations were performed in a sequential manner, the computerized method first, and then the conventional method. The animals were gently contained in the right lateral decubitus position. The tracings obtained by the conventional method were printed on thermally sensitive graph paper. The computerized method was performed in computer by means of specific software (TEB® ECGPC version 6.2), being the waves delimited by the observer. The tracings were also printed by means of a jet printer, and also interpreted. The morphology of P waves, QRS complexes and T waves were analyzed in the derivations: I, II, III, aVR, aVL and aVF. Heart rate, amplitude and duration of the P, QRS and T waves, PR, QT and heart rate (HR) intervals were calculated in derivation II. Mean electric axis was determined in leads I and III. Comparing the methods, there was a difference observed in the values of P and R waves, QRS complex, QT and PR intervals and T wave polarity. The interpretation of the evaluators presented statistical differences in the duration of the P wave, QRS, QT and HR. The three methods used presented differences during the mean of the interpretation of the evaluators.Discussion: Some factors such as the positioning of the animal and the use of chemical containment may influence the electrocardiographic tracings, as well as variations between electrocardiographic devices. In our study, the non-use of sedation and the use of the same equipment in all animals reduced the variability of the results. The interpretation of the computerized method printed and on the screen presented different results which can be explained by the reduced human visual capacity when compared to the computers. It is known that the interpretation of different tracings by the observers might influence the results of the examination. The evaluators of the present study evaluated the same tracings, but there was a difference in the interpretation of the observers. Regarding the methods, there was a difference between the three methods evaluated in relation to the ST segment. The computerized on-screen method demonstrated in its totality isoelectric ST segments that represent normal pattern for the species. The conventional and computerized printed methods presented results of elevation in ST segments that represent alterations in the diagnosis. There was a difference between the measurements performed by different observers, however this fact did not influence the results of the tests, since the parameters remained within the normality standards for species. It can be concluded that the variation between observers and among the three methods evaluated suggests that the ST segment interpretation is subtle and less influenced when performed in the computerized method.

Three-dimensional stress measurement for structural steel plates using ultrasonic T-waves and P-waves

Measurement ◽  
2022 ◽  
pp. 110310
Author(s):  
Yingzhu Wang ◽  
Nanxi Liu ◽  
Yunxuan Gong ◽  
Xupeng Zhu ◽  
Zuohua Li ◽  
...  
Keyword(s):  
Structural Steel ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Steel Plates ◽  
P Waves ◽  
T Waves

scholarly journals A preliminary study on normal electrocardiographic parameters of ostriches (Struthio camelus)

2007 ◽  
Vol 78 (1) ◽  
Author(s):  
A. Rezakhani ◽  
H. Komali ◽  
M.R. Mokhber-Dezfoul ◽  
M. Zarifi ◽  
M. Ghabi ◽  
...  
Keyword(s):  
Healthy Male ◽  
P Waves ◽  
Sinus Arrhythmia ◽  
Struthio Camelus ◽  
T Wave ◽  
Cardiac Dysrhythmias ◽  
Electrocardiographic Examination ◽  
Preliminary Study ◽  
Electrocardiographic Parameters ◽  
T Waves

Electrocardiograms were taken from 100 normal healthy male and female ostriches which were 1 to 15 months old using a base apex lead. The heart rate of those less than 3 months old ranged from 107 to 250 beats per minute with a mean of 171.47+9.03 and that of ostriches of more than 3 months old ranged from 43 to 167 with a mean of 90.52+2.64 beats / minute. The P-waves were positive in all cases except in 1 ostrich which it was isoelectric. The ORS complexes were mainly negative and either monophasic (QS) or biphasic (rS or RS). The T-wave showed more variation than other waves. The durations of P, P-R, QRS, Q-T and T-waves of chicks and of those more than 3 months of age (4-15-month-old) were 0.04 + 0.00, 0.06+0.00; 0.14+0.04, 0.16+0.00; 0.04+0.00, 0.06+0.00; 0.18+0.00, 0.27+0.00 and 0.06+0.00, 0.09+0.01 s, respectively, and amplitudes of the main direction of P-, QRS and T- waves of 2 groups were 0.29 + 0.02, 0.26 + 0.01; 1.87 + 0.17, 2.21 + 0.08; and 0.34 + 0.06, 0.37 + 0.02 mV, respectively. Ten cases showed cardiac dysrhythmias of which 9 showed sinus arrhythmia and 1 showed premature atrial contractions (PAC). This study showed that the base apex lead can be a suitable monitoring lead for electrocardiographic examination of ostriches.

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